In the case of carrying out a test by applying a predetermined stress such as a voltage to a self-heating electronic component at a predetermined test temperature, a cooling mechanism is conventionally used to keep the temperature of the electronic component within a certain range which otherwise exceeds the test temperature.
Further, as such a temperature control system, for example, Japanese Patent Application Laid-Open No. 2009-250810 proposes a temperature control system including: a cooling system including a flow channel through which a coolant flows, and a heat absorber and a heat radiator provided in the course of the flow channel, for cooling an electronic component by heat exchange through the heat absorber that is brought in direct or indirect contact with the electronic component to absorb the heat and through the heat radiator that radiates the heat absorbed by the heat absorber to the coolant; a heating system for heating the electronic component; and a controller for controlling the temperature of the electronic component by controlling the operation of the heating system, where the radiator of the cooling system is provided with a heat radiation member composed of a foam metal member.
Further, the thus configured temperature control system in Japanese Patent Application Laid-Open No. 2009-250810 is supposed to be able to control the temperature of an electronic component with excellent responsiveness even when the electronic component produces a large amount of heat due to self-heating, and makes it possible to conduct a characteristic inspection for the electronic component while keeping the temperature of the electronic component at a predetermined temperature with accuracy.
However, in this case of Japanese Patent Application Laid-Open No. 2009-250810, since a member (a heat conduction block (see FIG. 1 of Japanese Patent Application Laid-Open No. 2009-250810)) provided in a temperature sensor (a first temperature sensor 11 (see FIG. 1 of Japanese Patent Application Laid-Open No. 2009-250810)) has a large heat capacity, the temperature of the electronic component is estimated to be lower than it is because of diffusion of heat transferred from the electronic component, and thus, the system of Japanese Patent Application Laid-Open No. 2009-250810 is unable to accurately detect the temperature of the self-heating electronic component.
In particular, in the case of carrying out a test in which a voltage is applied to an electronic component with negative resistance-temperature characteristics, a phenomenon referred to as thermal runaway may be caused in which self-heating by electrical conduction increases the temperature, the temperature rise decreases the resistance to increase the electric current, and the current further increases self-heating. Therefore, feedback control cannot catch up with the self-heating of such an electronic component, thereby causing thermal runaway.
Furthermore, Japanese Patent Application Laid-Open No. 2008-275512 proposes an aging system in which a cooling plate subjected to heat exchange by a coolant supplied from a coolant supply unit is brought into contact with a self-heating sample body to cool the sample body for temperature regulation, the aging system including: a temperature detection unit for detecting the temperature of the sample body; and a coolant flow rate regulation unit for regulating the flow rate of the coolant supplied by the coolant supply unit on the basis of the result of detecting the temperature of the sample body by the temperature detection unit.
Further, this aging system is supposed to follow the change in the temperature of the self-heating sample body, thereby allowing the change in the temperature of the sample body to be reduced.
However, the aging system also has the problem of insufficiency due to the fact that a temperature sensor is attached directly to the sample body, and when there is a need to frequently replace a lot of electronic components and measure the temperatures, the operation of attaching the temperature sensor is produced every time the measurement target electronic component is replaced. Moreover, in the case of attaching the temperature sensor to the water-cooling plate, since the temperature of the sample body is not directly measured, the temperature of the electronic component is estimated to be lower than it is, and the same problem as with Japanese Patent Application Laid-Open No. 2009-250810 is caused, that is, the temperature of the self-heating electronic component cannot be accurately detected.